This invention relates to a color-image copying apparatus in which color image information on an original is illuminated with light from a light source, and is copied onto a recording medium on the basis of faithful hues.
In a conventional color-image copying apparatus, intensive light is emitted from a light source to illuminate an original, and reflecting light or transmitting light of the emitted light is utilized to faithfully copy color image information on an original, onto a recording medium. It is required for the light source to have a large quantity of light obtained easily, to be turned on instantaneously at the copying operation, and to have the cost reduced. A halogen lamp or the like (hereinafter referred to simply as "conventional light source") has conventionally been employed as the light source.
However, the conventional light source is low in luminescent efficiency so that a major part of the energy inputted is emitted as heat waves. By this reason, considerable heat is generated in order to obtain a light quantity sufficient for illumination of the original. This results in such problems as an increase in size of the equipment and an increase in the cost because of the measures to counter the heat such as heat radiation and the like.
Further, for copying the color image information by the use of the conventional light source, three kinds of monochromatic light sources such as, for example, three kinds of laser light sources are required to obtain three primary colors including red R, green G and blue B, and color filters are additionally required to adjust a ratio in light quantity among the three primary colors. This raises such problems as an increase in the number of component parts, complication of the optical system, an increase in the cost attendant thereon, and so on.